epa ghg regulations

Carbon Pollution Standards

The U.S. Environmental Protection Agency's (EPA) Clean Power Plan, proposed in June 2014, would limit carbon pollution from existing power plants.

Electric power generation is responsible for nearly 40 percent of U.S. carbon dioxide emissions – making it the largest single source. Reducing power sector emissions is a key part of President Obama’s Climate Action Plan, which aims to reduce overall U.S. greenhouse gas emissions 17 percent below 2005 levels by 2020. His June 2013 presidential memorandum directed EPA to set standards for both new and existing plants.

Under the Clean Power Plan for existing power plants, each state has its own target (due to regional variation in generation mix and electricity consumption). Overall, the rule is designed to cut emissions 30 percent from 2005 emissions by 2030, with an interim target of 25 percent on average between 2020 and 2029.

In September 2013, EPA released a “Carbon Pollution Standard for New Power Plants,” replacing a March 2012 proposal. EPA proposed standards for coal- and natural gas-fired plants (measured as tons of greenhouse gas emissions per megawatt-hour of elec­tricity produced) that states would apply at each regulated plant.

EPA will issue the finalize rules for the Clean Power Plan for existing power plants and the Carbon Pollution Standard for New Power Plants in the summer of 2015.

Explore the issues and options involved in EPA regulation of carbon pollution from power plants through the following resources.

In its proposed Clean Power Plan to reduce carbon dioxide emissions in the power sector, EPA has set a unique target emissions rate for each state to hit by 2030. To develop this target, EPA first determined a carbon emissions baseline (using 2012 data) based on each state’s level of CO2 emissions from fossil-fired power plants divided by its total electricity generation (including fossil-fired generation, renewable generation, and nuclear generation). Targets for 2030 were then established based on the capacity of each state to achieve reductions using the following four “building blocks” identified by EPA:

Make coal-fired power plants more efficient;

Use low-emitting natural gas combined cycle plants more where excess capacity is available;

Use more zero- and low-emitting power sources such as renewables and nuclear; and

Reduce electricity demand by using electricity more efficiently.

Since there is a wide variation among states in both emissions baseline and capacity to leverage each of the four building blocks, there is a wide variation in how much each state must cut from current emissions to hit its 2030 target emissions rate. (See Table 1.)

Each state can meet its established target however it sees fit, and does not need to leverage each building block to the extent that EPA projects. States will be able to convert their target emissions rate (pounds CO2 per megawatt-hour of electricity generated) to a mass-based standard (tons of CO2 emitted per year) to enable a cap-and-trade program. States are also free to join together and work toward an aggregated regional target.

*In the cases of Iowa, Maine, Minnesota, and South Dakota, the emission rate rises when building block three is added. The 2012 renewable generation levels in these states were higher than what EPA's methodology projects for 2030, meaning EPA assumes lower renewable generation, and therefore higher emission rates, for these states in 2030. These increases in emission rates are reflected by negative percentage changes for the effect of building block three when you click on these states in the map above.